Retardation controlled brake



Feb. 28, 1939; 7

E E. HEWITT RETARDATION CONTROLLED BRAKE Filed March 14, 1935 2Sheets-Sheet 1 INVENTOR BY ELLIS E.HEWI TT v ATTORN m m E NM Nm N mPatented Feb. 28, 1939 UNITED STATES PATENT OFFICE 12 Claims.

invention relates to retardation controlled brakes, and moreparticularly to brake systems for high speed railway trains in which therate of retardation produced by an application of the brakes isprevented from exceeding one or more desired'values.

Where railway trains are to be operated in high speed service it isdesirable that some means be provided for preventing the rate ofretardation produced by an application of the brakes from exceeding somedesired maximum value, so as to prevent sliding of the wheels and so asto make a smooth stop. In brake systems here-. tofore proposed for suchhigh speed trains. at device commonly referred to as a retardation con?troller device has been provided for this purpose. Kn example of a brakesystem employing such a device is well illustrated in my copendingapplication Serial No. 741,063, for a Brakeequipment, filed August 23,19.34,.

In brake systems of this character the retardation controller device isusually conditioned during service applications .of the brakes topre:vent rates .of retardation higher than a certain value, while uponinitiating emergency applica.- tions the retardation controller deviceis automat cally condit oned to p rm a hi he ra Whi e in eneral th maxmum e mitted r te may he ma ntained throughout the decelera ion P ri nga s rvi app ica on Without 1 419 discomfort to the passengers, orwithout prouci g v le t sh c throu hou t e rai at the o th shi i he hiher em enc ate is main a ne th u h u the e tir d ce em qn period thesame degree of comfort and freedom from shock may not result.Accordingly therefore, it is desirable during emergency applicationsthat the maximum rate of retardation be reduced near the end of thedeceleration period so that the train may be brought to a smooth stopfree of shock.

With these considerations in mind, it is a principal object of myinvention to provide a train braking equipment employing a retardationcontroller device, in which the maximum rate of retardation permitted bythe retardation controller device may be reduced at the will of theoperator near the end of the deceleration period, so as to make a smoothstop.

A further object of my invention is to provide specific meansforconditioninga retardation con- ;troller device during an-applioationof the brakes so that the maximum permitted rate of retardation will beautomatically diminished at the end .of the deceleration period;

permitted rate during emergency applications near the end of the stop.

Yet further objects and advantages, including novel arrangements ofspecific apparatus for accomplishing the foregoing and other objects,

will be apparent from the following description,

taken in connection with the attached drawings, wherein,

Figure 1 is a schematic view illustrating an embodiment of my inventiondepicted for the head end or control car of a train,'in which the partscomprising the embodiment have been illustrated more or lessdiagrammatically.

Figure 2 is a View diagrammatically indicating the functioning of therotary valve in the brake valve device illustrated at the top left ofFigure 1.

Figure 3 is a fragmentary view illustrating a modification ,of portionsof the apparatus shown in Figure 1.

Figure 4 is another fragmentary view illustrating still anothermodification .of the embodiment of Figure 1.

In the .completeembodiment shown in Figure 1, sufiicient apparatus forthe head end or control car only has been shown, but as the descriptionof the invention proceeds it will be apparent to those skilled in theart that by the duplication of certain .of the parts on succeeding cars,a complete train braking system results.

Considering the embodiment shown in Figure 1 briefly at first, there hasbeen provided a brake valve device it) for controlling all applicationsof the brakes. When a straight .air application of the brakes is to beeffected, the brake valve device l6 supplies fluid under-pressuredirectly to a brake cylinder l 2 and when applications areto be effectedby automatic operation the brake Valve device is operated to vent fluidunder pressure from abrake pipe 1,4.

For operating in response to service reductions in brake pipe pressureto supply fluid under pressure to the brake cylinder 12, I have provideda triple valve device I6, and ifor operating in response to emergencyreductions in brake pipe pressure to supply fluid under pressure to thebrake cylinder I have provided an emergency valve device [8.

For controlling the flow of fluid to the brake cylinder l2 during eithertype of brake application, so as to prevent the rate of retardation fromexceeding desired maximum values, there is provided a retardationcontroller device 2! For adjusting the retardation controller device toprovide for a reduced rate of retardation at the end of the decelerationperiod during an emergency application, there is provided a retardationcontrolling valve device 22, a self-lapping magnet valve device 24, anda speedometer rheostat 23.

Considering now these devices more in detail, the brake valve device Illcomprises a self -lapping portion 28, a rotary valve portion 30, and apipe bracket portion 32. These portions assembled together define apressure chamber 34.

The self-lapping portion 28 is provided for effecting and controllingapplications of the brakes during straight air operation. This portionis provided with a valve chamber 35 in which is disposed a supply valve33, urged toward a seat 33 by a spring 31. The valve chamber 35 is incommunication with a feed valve device 38 by way of passage 39 and pipe40. A check valve 4!, held seated by a spring 42, is disposed in thepassage 39, for a purpose which will appear later.

The self-lapping valve portion is also provided with a chamber 44 inwhich is operatively mounted a movable abutment 45 in the form of apiston, whichcontains interiorly thereof a release valve chamber 46.Disposed in the release valve chamber 46 is a release valve 41, which isurged away from its seat by a spring 48. The release valve 41 has aflanged extension adapted to engage a shoulder 49 on the movableabutment, to limit the travel of the release valve away from its seat.

The release valve chamber 45 is in communication with the pressurechamber 34 through a passage 5!) in the movable abutment. To the rightof the release valve seat, passages 5! lead. to the portion of chamber44 to the right of the movable abutment 45, and this portion of thechamber 44 is in communication with the atmosphere by way of passage 52.

The movable abutment 45 is subject on one side to fluid pressure in thepressure chamber 34 and on the other side to the pressure of aregulating spring 54. Tension on the spring 54 is regulated by aregulating member 55, which has a bore therein for receiving a guidingplunger 56 integral with the movable abutment, An adjusting screw 51 isprovided for regulating the extent of movement of the movable abutmentto the right.

It will thus be seen that thesupply valve 36 controls the supply offluid under pressure to the pressure chamber 34, and that the releasevalve 41 controls the release of fluid under pressure therefrom to theatmosphere.

For operating the supply valve 33 and the release valve 41, there isprovided a mechanism including spaced levers 63 carried intermediatetheir ends by a movable pivot carrier Bl slidably interfitting with abore 62 in the casing of the self-lapping portion. Rotatably disposedbetween the lower ends of the spaced levers 3b is a roller 63, which isadapted to engage the left end,'or stem, of the release valve 41.Loosely held between the upper ends of the spaced levers 60 is a member64 carrying a stem 65 having one end thereof disposed in a recess in thesupply valve 36.

The spaced levers 60 are intended to effect a seating of the releasevalve 41 and unseating of the supply valve 36 when the movable pivotcarrier 6| is actuated to the right. For actuating the pivot carrier 6!to the right, there is provided a cam 56 secured to an operating shaft61, which shaft is adapted to be rotated by movement of a handle 38. Theperipheral configuration of the cam 66 is such that when the handle 68is moved from release position toward an extreme application position,as will be more fully described later,

the cam actuates the movable pivot carrier 6(- progressively to theright.

Movement of the pivot carrier 3! to the right carries with it the spacedlevers 60. Now the supply valve spring 31 offers a greater resistance tothis movement than the release valve spring 48, while the regulatingspring 54 offers a greater resistance than either of these two springs.Therefore, upon movement of the pivot carrier to the right, the spacedlevers 60 fulcrum about their upper ends to first cause seating of therelease valve 41, and as this valve is seated the spaced levers fulcrumabout their lower ends to then unseat the supply valve 33. During thismovement of the spaced levers and the pivot carrier, the regulatingspring 54 is unappreciably compressed.

With'seating of the release valve 41 and unseating of the supply valve36, fluid under pressure is supplied from the feed valve device 38 tothe pressure chamber 34. The pressure chamber 34 is in constantcommunication with a straight air pipe 10, so that fluid under pressureflows through this straight air pipe to effect an app ication of thebrakes, as will be more fully described presently.

As the pressure in the pressure chamber 34 rises, it will act upon themovable abutment 45' to compress the regulating spring 54, and as thisspring is compressed the lower ends of the spaced levers 60 will move tothe right and the upper ends will move to the left, thereby permittingsupply valve 36 to seat. A little thought will show that if the pivotcarrier 61! is actuated to the right a given distance after the releasevalve 4! is seated, the supply valve 36 will be unseated a proportionaldistance. Therefore, the pressure required in the pressure chamber 34 toeifect seating of the supply valve by movement of the rawable abutmentto the right will likewise be proportional to this distance.

When the supply valve 35 is seated. the supply of fluid under pressureto the straight air pipe Hi will be lapped, and it will thus be apparentthat the pressure at which the supply laps is governed by the degree ofmovement of the pivot carrier 6! to the right. and hence according tothe degree of movement of the brake valve handle 68. The degree ofpressure established in the pressure chamber 34 then corresponds to thedegree or extent of movement of the handle 68 to application position.

The rotary valve portion 30 of the brake valve device comprises a casingdefining a rotary valve chamber 12 in which is disposed a rotary valve13. The rotary valve is held upon its seat in the pipe bracket section32 by a spring l4 and fluid pressure in the chamber 12. The rotary valve!3 is adapted to be rotated upon rotation of the shaft 61, to controlports and passages hereinafter more fully described. The rotary valvechamber 12 is in constant communication with the feed valve device 38,by way of passage 15 and pipe 40. A check valve 16 is disposed in thechamber 92 with the piston chamber 86;

passage. 15, for apurpose which will be described later.

The rotary valve'section30 is provided for controlling applications ofthe brakes" during automatic operation. Since both the self-lappingvalve portion and the rotary valve portion are operated from the onehandle'68, it will be apparent. that all applications of the brakes,whether by straight air operation orb-y automatic operation, may becontrolled by thesimplemanipulationi. of the one brake valve handle.

The emergency valve device I8 is embodied in a casingprovided with'aslide valve chamber. '58 anda piston chamber'ail. Disposed in the slidevalve chamber i8 is a main slide valve" 8| and mounted'upon themainslide valve is a graduating valve 82'. Disposed in the piston chamber isa piston 83' having a stem 84" for operating the two-slide valves; Thestem 84 is recessed toreceive' the graduating valve 82 so as to movethis valve coextensive withmovement of the piston 83. The stem 3'4 isprovided with shoulders 85 and86 for. engaging the main slide, valve 8|after a. lost motion movement of the piston 83.

The main slide valve 3| is held upon its seat by a loading mechanismcomprising a flexible diaphragm 88'mounted'in the casing of the valvedevice and adapted to. be urged into engagement with a rocking pin 89bearing upon the main slide valve. Aspring 90. exerts a constantdownward pressure upon the flexible diaphragm 88. The chamber above thediaphragm 88 is connected to apassage BI-so that when fluid underpressure is supplied to this passage a'further pres sure is exerteddownwardly upon the diaphragm 88.

The slide valve chamber 18 is in communication: with a quick actionchamber 92 formed in the casing, byway of passage 93,. A second passage94 also serves to connect the quick action This second'passageisnormally open when the'piston 33' is in releaseposition, as shown inFigure but when the piston moves outwardly to the left it disconnectsthis passage from the piston chamber 80.

The piston chamber Bil is in constant open communication with the brakepipe I 4' by way of pipe 96, so that brake pipe pressure is maintainedin the piston chamber.

Formed in a lower part of the casing of the emergency valve device is avent valve chamber 98 in which is disposed a vent valve 99 urged towardits seat I68 by a spring IGI. The vent valve chamber $8 is incommunication with the brake pipe I4 by way of pipe and passage )2 andthe aforementioned pipe 96. The vent valve 98 controls local venting ofthe brake 'pipe M, and hence of emergency piston chamber 8!! also, to achamber I03 which is in open communication with the atmosphere by way ofa large port I3 5.

For operating the vent valve 99 away from its seat there is provided avent valve piston 35.

When fluid under pressure is supplied to the space above the vent valvepiston at a rapid rate, the piston actuates the vent valve 99 tounseated position to vent fluid under pressure from the brake pipe I4,and from the piston chamber 88,-

to the atmosphere. When the supply of fluid under pressure to the spaceabove piston E05 is at a slow rate, it may leak around the piston bywayof leak grooves I06 without actuating the piston downwardly to unseatthe vent valve.

The main slide valve 8| is adapted to control ports and passages for apurpose and in a manner which will be more fully discussed in thedescription of operation of this embodiment of my invention.

The triple valve device I6 is embodied in a casing having a slide valvechamber I 08 and a piston chamber I09; Disposed in the slide valvechamber W8 is a main slide valve III] and mounted on top of the mainslide valve is a graduating valve III; Disposed in the piston chamberI99 is a piston H2 having a stem II3 recessed to receive the graduatingvalve III so as to move this valve coextensive with movement ofthepiston I I2. As may be seen from the drawing of Figure 1-, the pistonstem H3 is also provided with shoulders adapted to engage the main slidevalve H0 after a lost motion movement of the piston H2.

The piston chamber I09 is connected to the brake pipe I4 by way of theaforementioned pipe G6, and the slide valve chamber I I18 is in constantopen communication with an auxiliary reservoir i It by way of pipe I IS.The triple valve device i6 functions in response to service reductionsin brake pipe pressure, to control the supply of fiuidunder pressure toand its release from the brake cylinder E2, as willbe more fullydescribed hereinafter.

The retardation controller device 2!] is embodied in a casing providedwith a slide valve H8 adapted to control the flow of fluid through pipesH9 and 251 to the brake cylinder I2. The slide valve i I 8 is providedwith a cavity I20 which is adapted, in the position of the valve shownin the drawings, to permit flow to the brake cylinder, to cut oil flowthereto when moved to the right to an intermediate position, and torelease fluid under pressure from the brake cylinder in its i'arthermostposition to the right, through an exhaust port 2I0.

The slide valve H8 is urged toward its biased position to the left by aregulating spring I2I, which engages the right end of the slide valve,and toward various positions to the right by a body I34 moved accordingtothe rate of retardation of the vehicle. Tension on the spring I2! maybe adjusted by a service adjusting means comprising a spring I 22, whichacts upon a piston I23 disposed in a piston chamber I24. The piston I23has a stem pivotally connected at I25 to one end of a lever I26pivotally mounted intermediate itsends at I21 and adapted through itsotherend, which is bifurcated and straddles stem I32 so as to engage acollar thereon, to exert pressure on a movable abutment I28 to compressthe regulating spring I2I When the piston chamber I24 has been vented tothe atmosphere, the service adjusting spring E22 actuates piston I23 thefull distance to the right, whereupon the regulating spring I2! iscompressed according to the full expansion of the service adjustingspring I22. The tension thus placed on the regulating spring I26determines the maximum rateof retardation which is permissible duringservice application of the brakes.

For placing a greater tension on the regulating spring I 2| so as topermit a higher rate of retardation during emergency application of thebrakes, there is provided an emergency adjusting means comprising apiston I39 disposed in a piston chamber EM and having a piston sternFEE-adapted to engage the movable abutment i28. When the piston chamberI 3I is vented to the atmosphere, the piston I36 exerts no pressure onthe movable abutment I28, but when fluid under pressure is supplied toboth piston chambers I24 and I 3I upon initiating an emergencyapplication of the brakes, the pressure exerted on piston I30 iseffective in placing a greater tension on the regulating spring I2 I,while the pressure exerted on piston I23 holds the lever I26 againstmovement with rod I32 and thus releases the tension on the regulatingspring I 2| due to the service regulating spring I22. The retardationcontroller device is therefore conditioned to permit a higher rate ofretardation during emergency applications.

Movement of the slide valve I I8 to the right is governed by movement ofthe inertia operated body I34, which is provided with wings or flanges35 supporting the inertia operated body upon frictionless rollers I36.The body I34 is normally held in a biased position to the right byaction of theregulating spring I2I on the slide valve I I8, whichrotates a lever I3! about a pivot I38 to position the body I34.

The lever l3'I is provided with a roller I39 for engagement with thebody I34, and a similar roller I40 for engagement with the slide valveH8. When. the inertia operated body I34 is caused to move to the left,it rotates the lever I 3'! in a counterclockwise direction about itspivot I 38 to actuate the slide valve H3 to the right. The opposition tothe movement of the body and consequently the slide valve I I8,is'determined by the tension on the regulating spring I72 I.

The retardation controller device 26 is posi-- tioned on the vehicle ortrain so that the inertia operated body I34 is urged toward the leftwhen the train is decelerating. Therefore, it will be obvious that theslide valve IIB will be actuated to the right in accordance with therate of deceleration of the train, and that the distance which slidevalve I I8 is actuated will depend upon the tension on the regulatingspring I2I.

The retardation controlling valve device 22 is embodied in a casingprovided with a slide valve chamber 42 and a piston chamber I43.Disposed in the slide valve chamber I42 is a slide valve I 44, anddisposed in the piston chamber M3 is a piston I45 having a stem I46 foractuating the slide valve I44 coextensive with movement of the pistonI45.

The slide valve chamber I42 is in constant open communication with thefeed valve device 38 by way of pipe I48, while the slide valve chamberI42 has a restricted communication with the piston chamber I43 by way ofa restricted port H33 in the piston I45.

The piston I45 is normally held in a biased position to the right by aspring I50 so long as the pressures in the piston chamber I43 and slidevalve chamber M2 are substantially equal. When the pressure in pistonchamber I43 is suddenly reduced, the overbalancing pressure in the slidevalve chamber 42 actuates the piston to its extreme left hand position,to cause slide valve I44 to control ports and passages hereinafter morefully described.

For reducing the pressure in the piston chamber I43, there is provided avalve I5I, normally urged toward a seated position by a spring I52. Thevalve i5! is adapted to be actuated to unseated position upon downwardpressure exerted upon a push button I53. This push button has a pivotalconnection at I54 with the fluted stem of the valve I5I. Also associatedwith the push button l53 is a switch device having contacts I55 forcontrolling energization of the self-lapping magnet valve device 241 Theself-lapping magnet valve device 24 is embodied in a casing providedwith a supply valve I58, which is urged toward a seated position by aspring I59. The supply valve I58 has a stem terminating in a releasevalve I60 which coaots with a release valve seat in a slidable member I6|. When the release valve I66 is seated and the supply valve I58unseated, fluid under pressure is supplied from the feed valve device 38through pipe I43, branch pipe I62, and past the unseated supply valveI58 to a pipe I63. When the supply valve I58 is seated and the releasevalve I66 unseated, fluid under pressure supplied to the pipe I63, andhence to the volumes connected thereto, will be released to theatmosphere, past the unseated release valve I60 and through port I64.

For actuating the supply and release valves I 58 and I66 to unseated andseated positions, there is provided in the upper part of the casing anelectromagnet comprising a winding I66 suitably insulated from thecasing, and a movable core element I61. The movable core element I6? isheld in an upper position by a stem E68 having a spring cup I69 restingupon a spring I76.

When the winding I66 is energized, the movable core element I6'I isattracted downwardly toward a stationary core element I'II, compressingspring H6; and as a consequence a lower end of the stem I68 engages anidling stem I'l2 to actuate the slidable member I6I downwardly to firstseat the release valve I66 andto then unseat the supply valve I58. Thedegree to which the supply valve I 58 is unseated depends uponenergization of the winding I66, the greater the degree of energizationof this winding the greater the spring I'ID will be compressed.

Fluid under pressure supplied to the pipe I63 upon unseating of thesupply valve I58 also flows to a chamber II3 below a diaphragm I I4,which with the valve device casing defines the chamber ['53. Thediaphragm I14 is secured to the slidable member I6I, so that when thepressure acting below the diaphragm H4 overbalances that actingdownwardly upon the slidable member I6I due to energization of thewinding I66, the slidable member I6I will move upwardly until the supplyvalve I58 is seated, and as a result the supply of fluid under pressureto pipe I63 is cut ofi or lapped.

The resiliency of diaphragm lid is such that r the slidable member I6Iis urged upwardly, so that if the winding E is deenergized or itsenergization reduced, the slidable member IBI will move upwardly tounseat the release valve I66, to release fluid under pressure from thepipe 863 until the pressures on either side of diaphragm I14-substantially balance. The pressure of fluid supplied to pipe I63therefore depends upon the degree of energization of the winding I66.

For controlling energization of the winding I66, there is provided theaforementioned speedometer rheostat device 26. This device isessentially a speedometer of the type commonly employed to indicate thespeed of vehicles, such for example as the type commonly employed onautomobiles, and in general differs from the ordinary speedometer onlyin that the usual indicating dial has been replaced by a rheostat havingan arm IIB adapted to engage contacts llEl to cut in or cut out portionsof a resistance lBii. The resistance I83 is interposed in a circuitbetween a battery I6I and the winding H35, so that the amount ofresistance E65 in the circuit determines the degree of energization ofthe winding I66.

r The speedometer Thebst'at device is connected to a wheelof the'vehicle'or -train,or other rotating part rotating according to thespeed of the vehicle, by a "shaft member I82, and. when thevehicle ortrainis traveling at the maximum rate of speed, the arin I18 will bein'its extreme right'hand position, as shown in Figure 1. As the'speedof the train diminishes, the arm I78 moves toward its extreme lefthand position, thereby cutting in portions of the resistance I88. Itwill thus be see that when the push button I53 is depressed so 'thatcontacts I55 engage, winding I66 will be energized to a degree accordingtothe'spe'ed of the train.

The operation of this embodiment of my involition as applied to one carin a train is as follows: v I v p Running condition When the train isrunning, the brake valve handle 58 is maintained in Release position.

, In this position the brake pipe I d is maintained connected to thefeed valve device '38, by way of passage I34, -port I85 in rotary valvel3, rotary valvechamber 72, passage l5, and pipe 45. The feed valvedevice 38 is connected to a main reservoir I66, and, as is well known inthe art, functions to supplyfiuid under pressure from the main reservoirIBfi at a substantially constant pressure. This feed valve device is tobe understood as being one of the types commonly employed in the art forthis purpose.

, With. the brake pipe I 5 thus maintained charged to feedvalvepressure, both the quick action chamber 92 andthe auxiliary reservoir II5 are charged to the same pressure. 'I'hequick actiomchamber S2, issupplied from the brake pipe I4 by way of pipe 96, emergency pistonchamber 86, and passage ,94, while the auxiliary reservoir I I5 issupplied through pipe 96, triple valve piston chamber I09, feed grooveI88, slide valve chamber 193, and pipe IIB. ,So long as the brakepipe ismaintained charged, triple piston II? will b85l1311d in its left handposition and emergency valve device piston 83 will be held inits righthand position, as shown in Figure 1. In the retardation controllerdevice 29, the piston chamberlzd will be vented to the atmosphere by way{of pipe I89, port ISO in slide valve hi4 of the retardation controllingvalve device 22, and through exhaust passage IB'I. At the same time,piston chamber ,I 3I also will be vented to the atmosphere ,by Way ofpipe I92, cavity I 93 in slide valve I44, pipe I94; cavity I96 in slidevalve 8] of the emergency valve device I8, and exhaust port I91. Theservice regulating spring I2 2 will therefore be effective in placing afixed tension on the regulating spring I 2I, and the retardationcontroller device will therefore be set to limit the rate of retardationfor service applic'ations of the brakes substantially to a fixed value.

Service applications by straight air operation When it is desired toeffect a service application of the brakes, by straight air operation,the brake valve handle 68 is moved through the zone indicated in Figure2 as Strai'ght air Zone to a degree or extent in accordance with adesired degree of braking. During this movement the cam :56 actuates thepivot-carrier 6| to theright to first .seat the release valve 41, and tothen unseat .the' sup-ply valve 36.

.Fluid under pressure thenlfiows .from..-the feed valve device 3.8through pipe I passage .39,=where it 'unseats the ball check valve 4|,supply valve chamber 35, to the pressure chamber 34.

From the pressure chamber 34, the flow is through passage I98, Ja firstportion of straight air pipe "It, passage I99 in the emergency valvedevice, cavity 2% inslide valve SI, passages 20I and 9|, and a secondportion of the straight ,air pipe it to a chamber 202 in a double checkvalve device 204. 'In this double check valve device a valve 285 isactuated to the right by the pressure of 'the fluid, to uncover apassage 296, and fluid then flows from the chamber 202 through pipeizll,cavity 12% of retardation controller slide valve H8, and pipe I 59 tobrake cylinder I2. As the pressure in the brake cylinder I2 builds upthe brakes are thus applied.

As soon as the pressure in the pressure champer 35, of the brake valvedevice 'I0,'has reached a value corresponding to the degree or extent ofmovement of handle 68, the movable abutment 25 will "move-a sufficientdistance to the right to lap the supply and consequently the brakes willbe applied to a degree corresponding to the degre'eor extent of movementof the handle '68.

During this operation of the brake valve device I0, 'theb'rake pipe I4is maintained connected to the feed valve device 38, as isdiagrammatically indicated in Figure 2. When fluid under pressure issupplied to the brake cylinder by straight air operation, there may bean appreciable momentary drop in pressure in pipe 40 adjacent the feedvalve device 38. If the check valve 16 in the brake valve device werenot provided, this drop in pressure may be reflected in the brake pipel4 a d t us a e. a u e e o e t on. of ithe th tr pl lv dev ce .15 o h men y valve device I8. However, the check yalvedevice I3 prevents areduction of the pressure in the brake pin whil lu is b in su li to hbrake cylinder during straight air operation, so that it will be seenthat neither the triple valve device I5 nor the emergency valve deviceI8 are operated during straight air applications of th ra ,7

Fluid flowing to the brake cylinder I2 through a sa e .9 a so fi wsi thchamber ove aphragm 68 where it exerts a downward p essure upon thediaphragm in addition to that exerted by spring 90, so as to hold themain slide valve BI upon its seat. H p H,

. Assumin now ha th ldesr o pp a of the brakes has been sufficient tocause functioning 9i the ret'ardationcontroller device 20, the inertiaoperated body I34 will move to the left and actuate the slide valve IIBto the right. When the slide valve IIB has beenactuated far enough toblankthe passage connecting with pipe 201, the brake cylinder will beisolated from the supply of fluid under pressure. If the rate ofretardation should increase iurtherso that the slide valve ,I {8 isactuated to the right for enough to connect pipe HQ with exhaust port2), fluid under pressure will be released from the brake cylinder.

The release of fluid under pressure from the brake cylinder willcontinue until the rate of retardation has been diminished sufficientlyto cause the body .I 34 to move toward the right, whereupon slide valveII8 will disconnect pipe II9 from exhaust port -2I0. The supply to thebrake cylinder will then againbe lapped.

:If new with diminishing speed the coefficient of frictionbetween therubbingrparts of the brakes shouldincrease .sufiiciently to cause therate of retardation :tO again rise, a further release of fluid underpressure from the brake cylinder will be effected by the retardationcontroller device. It will be obvious therefore that the retardationcontroller device 20 will thereafter function to intermittently reducethe brake cylinder pressure, so as to maintain a rate of retardationcorresponding to the tension on the regulating spring l2l.

Since during this application of the brakes the fixed tension on the.regulating spring \l2l is maintained constant throughout the operationof the retardation controller device, it will be apparent that so longas the retardation controller device is controlling the brake cylinderpressure the rate of retardation will be maintained at a substantiallyconstant value throughout the entire deceleration period.

When it is desired to efiect a release of the brakes at any time, thebrake valve handle 68 is turned to release position. In this positionthe release valve 41 is unseated and fluid under pressure is releasedfrom the pressure chamber 34, to the atmosphere. If the train is at restwhen this release is effected, fluid under pressure will be releasedfrom the brake cylinder l2 through the same communication through whichit was supplied, but if .the release is made at a time when theretardation controller slide valve H8 blanks pipe 201, then check valve2|2 in the retardation controller device will unseat to permit flow of,fluid from the brake cylinder to the brake valve device.

Service applications by automatic operation If for any reason thestraight air portion of the brake equipment should be renderedinoperative, then service applications may be effected by automaticoperation. To efiect a service application of the brakes by automaticoperation, the brake valve handle 68 is turned to the position indicatedin Figure 2 as Automatic service position. In this position the brakepipe I4 is disconnected from the feed valve device 38, and reconnectedto an exhaust port 214 by way of a port in the rotary valve having arestriction 2l5 therein. The brake pipe is thus vented to theatmosphere, with the handle 68 held in the automatic service positionfor a time suflicient to reduce the brake pipe pressure according to thedesired degree of braking, after which the handle 68 is turned to theposition indicated as Lap in Figure 2.

When the pressure in the brake pipe is thus reduced, triple valve pistonH2 moves to the right due to the overbalancing pressure from the slidevalve chamber I08. This movement of the piston closes the feed grooveI88 and first carries the graduating valve ill to the position wheremain slide valve port 2H5 is uncovered, and then carries the main slidevalve H to the position where this port 2H3 registers with a passageconnecting with pipe. 2H. Fluid under pressure then flows from theauxiliary reservoir H5 through port 2| 6, and pipe 2 I l, to the rightof valve 205 in double check valve device 204. The valve 205 is thenactuated to the left by the pressure of this fluid and the flow is thento the brake cylinder through the retardation controller 20 asheretofore described.

When the pressure on the left side of triple piston H2 becomes slightlybelow that on the right side, the piston will move to the left untilgraduating valve lll blanks the main slide valve port H6. ,The supply offluid under pressure to the brake cylinder will then belapped.

At the same time the triple valve device I6 is operating, the emergencyvalve device piston 83 moves to the left far enough to blank passage 94leading to the quick action chamber 92, and far enough for port H8 inthe graduating valve 82 to register with port 220 in the main slidevalve 8i but not far enough to uncover main slide valve port 22!. Fluidunder pressure in the slide valve chamber 78, and quick action chamber92, then flows through ports 218 and 220 to the atmosphere by way ofexhaust port 222.

The port 2H3 is so proportioned that the rate of drop inpressure inslide valve chamber 18 corresponds to the rate of drop in pressure inpiston chamber 80, so that the piston 83 is arrested in the position inwhich ports 218 and 220 register. As soon as the pressure in slide valvechamber 18 drops below that in piston chamber 80, piston 83 moves towardthe right and graduating valve 82 blanks the main slide valve port 220,The emergency valve device is thus caused to remain inoperative duringservice reductions in brake pipe pressure and, as will be more fullyexplained later, operatesonly in response to emergency reductions inbrake pipe pressure. g

It is intended that service applications of the brakes by automaticoperation shall be effected only when the straight air portion of theequipment is inoperative. Of course if the straight air portion wereoperative, movement of the brake valve handle 58 to automatic serviceposition would result in both straight air and automatic operation. Itis preferable that the ultimate pressure of the fluid supplied by thefeed valve device 38 shall be maintained greater than that supplied bythe auxiliary reservoir H5, so that in such cases the double check valve205 would remain to the right, as shown, and the application would beeffected by straight air operation only.

During an automatic application of the brakes, the retardationcontroller device 20 is conditioned the same as for service applicationsby straight air operation, so that if the degree of application issufficient to cause functioning of the retardation controller device, itwill operate in the same manner as described for straight airapplications. The maximum permitted rate' is therefore the same for bothservice applications.

When it is desired to effect a release of the brakes following anautomatic service application, the brake valve handle 68 is turned backto release position. In this position, as will be noted from Figure 2,the brake pipe is again connected to the feed valve device 38, and, uponrestoration of the pressure in the brake pipe, triple piston 2l2 movesback to its release position, where pipe 2|! is connected to exhaustport 224, by way of cavity 225 in slide valve H0. Fluid under pressurewill then be released from the brake cylinder l2, through pipe 2H,cavity 225, and exhaust port 224 to the atmosphere.

Emergency applications When it is desired to effect an emergencyapplication of the brakes, the brake valve handle 68 is turned to theposition indicated in Figure 2 as Emergency position. In this positionof the brake valve handle, the cam 66 actuates the pivot carrier 6! themaximum distance to the right, and at the same time the rotary valve l3disconnects the brake pipe l4 from the feed valvedevice 38, andreconnects the brake pipe to exhaust port 2I4 through an enlarged port228 in the rotary valve.

Movement of the pivot carrier BI to the right actuates the self-lappingvalve portion 28 to permit fluid pressure in pressure chamber 34 tobuild up to the maximum possible degree. Connection of the brake pipe tothe atmosphere through enlarged port 228 vents the brake pipe to theatmosphere to reduce the pressure therein at an emergency rate.

When the pressure in the brake pipe is reduced at an emergency rate, theemergency piston 83 in the emergency valve device 22 is caused to moveto the left far enough for graduating valve 82 to uncover main slidevalve port 22I. Fluid under pressure then flows from the slide valvechamber I8, and quick action chamber 92, to the space above the ventvalve piston I05, and this flow takes place at a rapid rate so thatsufficient pressure builds up above the vent valve piston to actuate thepiston downwardly to unseat vent valve 99.

Unseating of vent valve 99 further vents fluid under pressure from thebrake pipe I4, and piston chamber 88, to the atmosphere by way ofexhaust port I84, so that there is a sharp drop in pressure immediatelyadjacent emergency piston 83. This drop takes place to a degree suchthat the overbalancing pressure to the right of the piston actuates itto its extreme position to the left. The slide valve 8|, which up tothis time has remained at rest, is thus moved to application position.

In application position, main slide valve 8I blanks the passage I99 andconnects passage 20I to another passage 230 by way of port 23I in theslide valve. The passage 230 is connected to the feed valve device 38,by way of pipes 232 and I 48, so that fluid under pressure flowsdirectly from the feed valve device through pipes I48 and 232, passage238, cavity 23I, passage 28I, straight air pipe III, to the double checkvalve chamber 282, from whence it flows to the brake cylinder as beforedescribed, Emergency valve device I8 therefore functions to connect thefeed valve device direct to the brake cylinder through a communicationwhich by-passes the brake valve device III.

In response to the emergency reduction in brake pipe pressure, triplevalve piston I I2 moves to its extreme right hand position where mainslide valve port 2I6 registers with the passage connecting with pipe2I'I, but the double check valve 285 will blank flow from the auxiliaryreservoir H5, unless there has been a failure of the supply effectedthrough operation of the emergency valve device.

In the emergency valve device I8, cavity 208 in the main slide valve 8|connects passages 2M and 234, so that fluid under pressure flowing tothe brake cylinder also flows through passage 234, pipe I94, cavity I93in slide valve I44, and pipe I92 to piston chamber I III in theretardationcontroller device 28. A tension is thus placed on theregulating spring I2I corresponding to feedvalve pressure acting uponpiston I 30. If no further acts on the part of the operator wereperformed than heretofore described then, the retardation controllerdevice 20 would thus be conditioned to permit a single maximum rate ofretardation throughout the entire deceleration period, which mightproduce too abrupt a stop at the end.

If now the operator desires to make a smooth stop, he depresses the pushbutton I53, thereby closing contacts I55 and unseating the valve II.

Unseating of valve I5I vents the piston chamber I43 to the atmospherepast the unseated valve, and the overbalancing pressure in slide valvechamber I42 actuates the piston to its extreme left hand position,thereby compressing the spring I50. In this position of the piston, theslide valve I44 connects pipe I63 with pipe I92 by way of port 236 andbrings slide valve port 23'! into registration with the .passageconnecting with pipe I89. At this time the other passages in the slidevalve seat are blanked. The choke port I49 in piston I45 is small enoughto prevent undue loss of fluid during this operation of the valvedevice.

Closing of contacts I55 completes a circuit to the magnet valve devicewinding I66, through the speedometer rheostat device 26. If the speed atwhich the train is traveling is a maximum, rheostat arm IIB will be inthe position shown in Figure 1 and consequently the winding I 85 will beenergized to a maximum degree. If the rheostat arm H8 is in someintermediate position, the winding I66 will be energized to a lowerdegree.

For any degree of energization, however, the winding I66 causes seatingof release valve I 88 and unseating of supply valve I58, whereupon fluidunder pressure flows from the feed valve device through pipe I48, branchpipe I62, past the unseated supply valve I58, through pipe I63, slidevalve port 236, and pipe I92, to retardation controller piston chamberI3I. It will thus be evident that the pressure of fluid supplied to thepiston chamber I3I will thereafter be controlled according toenergization of winding I68 in the magnet valve device 24. The tensionon regulating spring I2I will therefore be adjusted according to thespeed of the vehicle.

Registration of slide valve port 23?, in the retardation controllingvalve device 22, with the pipe I89 supplies fluid under pressure fromthe slide valve chamber I42, and feed valve device 38, through thisport, and pipe I89, to the retardation controller piston chamber I24.The pressure of fluid supplied to this chamber is thus at feed valvepressure, so that the piston i23 is actuated to the left compressing theservice regulating spring I22. The effect of this is to rotate the leverI26 to unload the regulating spring 225 from any pressure which might beeffected by th-e'service regulating spring I22.

Since the operation of the emergency valve device 22 was to connect thebrake cylinder I2 direct to the feed valve device 38, it will be evidentthat the degree of braking produced will be a maximum, and that theretardation controller device 20 will subsequently take control andregulate the brake cylinder pressure so as to maintain a varied rate ofretardation according to the tension on the regulating spring I2I.

In order that the emergency vent valve 93 shall be closed shortly afterthe brake pipe has been reduced at an emergency rate, a leak port 248has been provided in the vent valve piston I85, so that after apredetermined length of time the pressure above the piston, and in slidevalve chamber I8 and quick action chamber 92, will have been released tothe atmosphere, and spring I8I will thereafter seat the vent valve.

During operation of the emergency valve device I8, it will be noted thatthe main slide valve 8I is loaded through operation of the diaphragm 88in the same manner as described for service applications.

When. it is desired to effect a release of the brakes following anemergency application, the brake valve handle 58 is turned to releaseposition. In this position, the brake pipe is reconnected to the feedvalve device, as before explained for a release following an automaticservice application, and the pressure in the brake pipe is restored.Triple piston 2 I2 and emergency valve device piston 83 then return torelease position and fiuid under pressure is released from the brakecylinder through the self -lapping portion 28 of the brake valve device,as described for a straight air application.

Modification shown in Figure 3 In Figure 3 is shown a modification of aportion of the apparatus depicted in Figure 1, whereby the tensionplaced on the regulating spring I 2I of the retardation controllerdevice 28 is controlled according to brake cylinder pressure. As will beseen from this figure, pipe I63, which was connected to the self-lappingmagnet valve device 24 in Figure l, is now connected to the brakecylinder I2. The retardation controlling valve device 22 is the same asthat shown in Figure 1, except that the push button I53 is now maderigid with the stem of valve I5I, and the switch contacts I55 areomitted.

If during an emergency application of the brakes the operator desires tohave the rate of retardation reduced toward the 'end of the decelerationperiod, he presses the push button I53, as before, and the pressure offiuid supplied to the retardation controller piston chamber iii nowcorresponds to brake cylinder pressure, so that the tension placed onregulating spring Iii decreases as the pressure in the brake cylinder isdecreased.

From the use of like numerals in Figure 3 to indicate like parts inFigure 1, it will be observed that the remainder of the apparatus shownhas been unchanged.

Modification shown in Figure 4 In'Figure 4 I have shown a furthermodification of the means for regulating the tension on the regulatingspring I2I, in which the tension of this regulating spring is governedeither by brake pipe pressure or by the operation of a centrifugedevice.

The piston chamber I24, heretofore referred to, is now connected to thebrake pipe I4 by way of branch pipe 238, instead of being connected tothe retardation controlling valve device 22, as shown in Figure l. Thepiston I23 is therefore subject to brake pipe pressure at all times.When the brake pipe is charged, the piston I23 is held to the left whereit compresses the spring I22. In this position of the piston I23, thelower end of lever I28 compresses the regulating spring I2I through theabutment 239 only to the desired degree for conditioning the retardationcontroller device for limiting the rate of retardation during serviceapplications.

'When an emergency application of the brakes is effected by a reductionin brake pipe pressure, the piston I28 moves to the right and additionaltension is then placed on the regulating spring I2! by expansion of thespring I22. If the operator desires to make a smooth stop, he depressesthe push button 2: inthe valve device 242, which has now replaced theretardation controlling valve device 22 of Figure 1. This unseats avalve 243, which connects the aforementioned pipe I48 leading to thefeed valve device 38 with another pipe 244, which leads to a pistonchamber 245 having a piston 246 disposed therein. The pressure of thefluid supplied from the feed valve device to this piston chamberactuates piston 246 to the right, compressing spring 247, and thusmoving the fulcrum point of lever I26 to the right so that the tensionplaced on the regulating spring MI by expansion of the spring I22 isreleased.

Thereafter the tension placed on the regulating spring IZI is controlledby a centrifuge device 259 in accordance with the outward movement ofcentrifuge weights 253i which act upon a stem 252 to actuate it to theleft against opposition of a spring 253. The weights 25I are rotated ata speed proportional to vehicle speed, through gears 24% and shaft 259.

When the train is traveling at or near its maximum speed, the centrifugeweights 25I will be in their outermost position and stem 252 will thenengage a pivoted finger 25$ to actuate it into engagement with anotherstem 255 and thus cause the stem to push the abutment 25 .8 to the leftto place a maximum tension on spring E2i. As the speed of the vehiclediminishes the tension on the regulating spring I2I will diminish, sothat the maximum rate of retardation permitted by the retardationcontroller diminishes according to the decrease in speed.

It will thus be seen from the various embodim nts shown that I haveprovided a number of ways in which the adjustment of the retardationcontroller device may be controlled, and in each case the maximumpermitted rate may be decreased toward the end of the deceleration period, so that a smooth stop may be made.

While I have described one complete embodiment of my invention and twomodifications thereof, it is to be understood that I do not desire to belimited to these specific embodiments or otherwise than by the spiritand scope of the appended claims.

I-laving now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a vehicle brake system, in combination, a brake cylinder, meansfor effecting a supply of fluid under pressure to the brake cylinder, are tardation controller device having an element movable according tothe rate of retardation of the vehicle, means responsive to movement ofsaid element for controlling the supply of fluid under pressure to andits release from the brake cylinder, fluid pressure controlled means forcontrolling movement of said element, electroresponsive valve means forcontrolling supply of fluid under pressure to said fiuid pressurecontrolled means, and speed controlled means for controlling saidelectroresponsive valve means.

2. In a vehicle brake system, in combination, a retardation controllerdevice having an element movable according to the rate of retardation ofthe vehicle, yielding means for opposing movement of said element,service regulating means for conditioning said yielding means duringservice applications of the brakes, emergency regulating means forconditioning said yielding means during emergency applications of thebrakes, means for rendering said service means ineffective and forrendering said emergency means effective according to the speed of thevehicle, brake means, and means responsive to movement of said elementfor controlling said brake means.

3. In a vehicle brake system, in combination, a retardation controllerdevice having an element movable according to the rate of retardation ofthe vehicle, yielding means for opposing movement of said element, fluidpressure operated service means for conditioning said yielding meansduring service application of the brakes, fluid pressure operatedemergency means for conditioning said yielding" means during emergencyapplication of the brakes, said service means being rendered ineffectiveand said emergency means being rendered efFective upon the supply offluid under pressure to each, a valve device having a biasedposition-andbeing operable to a position to supply fluid under pressureto both said service means and said emergency means, means forcontrolling the degree of fluid supplied to said emergency meansaccording to the speed of the vehicle, brake means, and means responsiveto movement of said element for controlling said bra-kemeans.

4". In avehicle brake system, in combination, a brake cylinder, meansfor effecting a supply of fluid under pressure to the brake cylinder, aretardation controller devicehaving an element movable according to therateof retardation of the vehicle, means responsivetomovement of saidelement for controlling said supply, yielding means for opposingmovement of said element, fluid pressure operated means for conditioningsaid yielding means to oppose movement of said element according to thesupply of fluid under pressure thereto, electroresponsive valve meansoperable to supply fluid under pressure to operate said fluid pressureoperated means according to the degree of energization thereof, andspeed controlled means for controlling the degree of energization ofsaid electroresponsive valve means.

5. In a vehicle brake system, in combination, a brake cylinder, meansfor effecting a supply of fluid under pressure to the brake cylinder, aretardation controller device having an element movable according to therate of retardation of the vehicle, a spring for opposing movement ofsaid element, service conditioning means for normally exerting asubstantially constant pressure on said spring and operable upon thesupply of fluid under pressure thereto to release pressure on saidspring, emergency conditioning means operable to exert a pressure uponsaid spring according to the degree of pressure of fluid suppliedthereto, a valve device having a normally biased position and beingoperable to a position for supplying fluid under pressure to both saidservice means and emergency means, an electroresponsive valve device forcontrolling the supply of fluid under pressure to said emergency meansaccording to the degree of energization thereof, a rheostat deviceoperated according to the speed of the vehicle for controllingenergization of said electroresponsive valve means, and means responsiveto a predetermined movement of said element for efiecting a release offluid under pressure from thebrake cylinder.

6. In a vehicle brake system, in combination, brake means, means foreffecting either a service application or an emergency application ofsaid brake means, a retardation controlled device operated according tothe rate of retardation of the vehicle, means responsive to operation ofsaid retardation controller device for controlling the degree ofapplication of said brake means, means for conditioning said retardationcontroller device to permit one maximum rate of retardation duringservice applications and to permit a higher rate during emergencyapplications, and means selective at the will of the operator forcontrolling said last means during emergency applications of the brakesto vary the maximum permissible rate of retardation according to thespeed of the vehicle.

7. In a vehicle brake system, in combination, a brake cylinder, a firstvalve means operable to supply fluid under pressure to' the brakecylinder to effect a service application of the brakes, a second valvemeans operable to supply fluid under pressure to the brake cylinder toeiiect an emergency application of the brakes, a retardation controllerdevice having an element movable according to the rate of retardation ofthe vehicle, means operable upon a predetermined movement of saidelement for first cutting off the supply to and then releasing fluidunder pressure from the brake cylinder, resilient means for opposingmovement of said element, service conditioning means for exertingasubstantially constant pressure on said resilient means and operableupon the supply of fluid under pressure thereto to: release saidpressure, emergency" conditioning means operable to exert pressure onsaid resilient means according to the supply of fluid under pressurethereto, said second valve means being operable tosupply fluid underpressure to said emergency conditioning means to a degree correspondingto the degree of fluid under pressure supplied thereby to the brakecylinder, and means selective at the will of an operator forsubsequently varying the pressure of fluid supplied to said emergencyconditioning means according to the speed of the vehicle.

8. In a vehicle brake system, in combination, a brake cylinder, meansfor effecting a supply of fluid under pressure to the brake cylinder, aretardation controller device having an element movable according to therate of retardation of the vehicle, means responsive to a predeterminedmovement of said element for first cutting oif and then releasing fluidunder pressure from the brake cylinder, yielding means for opposingmovement of said element, fluid pressure operated means for causing saidyielding means to oppose movement of said element according to thedegree of pressure of fluid supplied thereto, means operable whenefiecting an application of the brakes to supply fluid under pressure tosaid fluid pressure operated means according to the pressure of fluidsupplied to the brake cylinder, an electroresponsive valve deviceoperable to control the pressure of fluid supplied to said fluidpressure operated means according to the degree of energization thereof,speed controlled means for controlling the degree of energization ofsaid electroresponsive valve means according to the speed of thevehicle, and means selective at will for rendering saidelectroresponsive valve means eflective in controlling the pressure offluid supplied to said fluid pressure operated means.

9. In a vehicle brake system, in combination, brake means, a retardationcontroller device having an element movable according to the rate ofretardation of the vehicle, means responsive to a predetermined movementof said element for efiecting a release of said brake means, yieldingmeans for opposing movement of said element, a brake pipe, meansoperated upon a reduction in brake pipe pressure for conditioning saidyielding means to oppose movement of said element with a force ofopposition proportional to the reduction in brake pipe pressure, acentrifuge device operated according to the speed of the vehicle, andmeans selective at will for transferring the conditioning of saidyielding means to said centrifuge device.

10. In a vehicle brake system, in combination,

a brake cylinder, means for effecting a supply of fluid under pressureto the brake cylinder by straight air operation, means for efiecting asupply of fluid under pressure to the brake cylinder by automaticoperation, a retardation controller device having an element movableaccording to the rate of retardation of the vehicle, valve meansresponsive to movement of said element for controlling the supply offluid under pressure to and its release from the brake cylinder Whethersupplied by straight air operation or by automatic operation, yieldingmeans for opposing movement of said element, service conditioning meansfor conditioning said yielding means only during straight air operation,emergency conditioning means for conditioningsaid yielding means onlyduring automatic operation, and means operable during automaticoperation to control said emergency conditioning means according to thespeed of the vehicle.

11. In a Vehicle brake system, in combination, a retardation controllerdevice havingan element movable according to the rate of retardation ofthe vehicle, yielding means for opposing movement of said element,service regulating means for conditioning said yielding means duringservice applications of the brakes, emergency regulating means forconditioning said yielding means during emergency applications of thebrakes, and means for rendering said service means inefiective and forrendering said emergency means effective according to the speed of thevehicle.

12. In a vehicle brake system, in combination, fluid pressure brakemeans, a source of supply of fluid under pressure, a brake pipe,automatic valve means operable upon a reduction in brake pipe pressurefor supplying fluid under pressure to efiect an application of saidbrake means, a brake valve device operable to also efiect a supply offluid under pressure from said source to effect an application of saidbrake means, said brake valve device establishing and maintaining acommunication between said source and said brake pipe during saidoperation, and. a check valve device operable to prevent fluctuations inbrake pipe pressure when the pressure of said source is diminished dueto the supply of fluid effected by said operation of said brake valvedevice.

ELLIS E. HEWITT.

